Question

我正在尝试加密/解密XML文件。我发现这个样本用于加密但我不知道如何解密？任何的想法？谢谢！

        // Load this XML file
        System.Xml.XmlDocument myDoc = new System.Xml.XmlDocument();
        myDoc.Load(@"c:\persons.xml");
        // Get a specified element to be encrypted
        System.Xml.XmlElement element = myDoc.GetElementsByTagName("Persons")[0] as System.Xml.XmlElement;

        // Create a new TripleDES key. 
        System.Security.Cryptography.TripleDESCryptoServiceProvider tDESkey = new System.Security.Cryptography.TripleDESCryptoServiceProvider();

        // Form a Encrypted XML with the Key
        System.Security.Cryptography.Xml.EncryptedXml encr = new System.Security.Cryptography.Xml.EncryptedXml();
        encr.AddKeyNameMapping("Deskey", tDESkey);

        // Encrypt the element data
        System.Security.Cryptography.Xml.EncryptedData ed = encr.Encrypt(element, "Deskey");

        // Replace the existing data with the encrypted data
        System.Security.Cryptography.Xml.EncryptedXml.ReplaceElement(element, ed, false);

        // saves the xml file with encrypted data
        myDoc.Save(@"c:\encryptedpersons.xml");

但我不知道如何解密呢？有任何想法吗？谢谢！

Answer 1

这样的事情：

public static class Encryption
{
    private const string InitVector = "T=A4rAzu94ez-dra";
    private const int KeySize = 256;
    private const int PasswordIterations = 1000; //2;
    private const string SaltValue = "d=?ustAF=UstenAr3B@pRu8=ner5sW&h59_Xe9P2za-eFr2fa&ePHE@ras!a+uc@";

    public static string Decrypt(string encryptedText, string passPhrase)
    {
        byte[] encryptedTextBytes = Convert.FromBase64String(encryptedText);
        byte[] initVectorBytes = Encoding.UTF8.GetBytes(InitVector);
        byte[] passwordBytes = Encoding.UTF8.GetBytes(passPhrase);
        string plainText;
        byte[] saltValueBytes = Encoding.UTF8.GetBytes(SaltValue);

        Rfc2898DeriveBytes password = new Rfc2898DeriveBytes(passwordBytes, saltValueBytes, PasswordIterations);
        byte[] keyBytes = password.GetBytes(KeySize / 8);

        RijndaelManaged rijndaelManaged = new RijndaelManaged { Mode = CipherMode.CBC };

        try
        {
            using (ICryptoTransform decryptor = rijndaelManaged.CreateDecryptor(keyBytes, initVectorBytes))
            {
                using (MemoryStream memoryStream = new MemoryStream(encryptedTextBytes))
                {
                    using (CryptoStream cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read))
                    {
                        //TODO: Need to look into this more. Assuming encrypted text is longer than plain but there is probably a better way
                        byte[] plainTextBytes = new byte[encryptedTextBytes.Length];

                        int decryptedByteCount = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length);
                        plainText = Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount);
                    }
                }
            }
        }
        catch (CryptographicException)
        {
            plainText = string.Empty; // Assume the error is caused by an invalid password
        }

        return plainText;
    }

    public static string Encrypt(string plainText, string passPhrase)
    {
        string encryptedText;
        byte[] initVectorBytes = Encoding.UTF8.GetBytes(InitVector);
        byte[] passwordBytes = Encoding.UTF8.GetBytes(passPhrase);
        byte[] plainTextBytes = Encoding.UTF8.GetBytes(plainText);
        byte[] saltValueBytes = Encoding.UTF8.GetBytes(SaltValue);

        Rfc2898DeriveBytes password = new Rfc2898DeriveBytes(passwordBytes, saltValueBytes, PasswordIterations);
        byte[] keyBytes = password.GetBytes(KeySize / 8);

        RijndaelManaged rijndaelManaged = new RijndaelManaged {Mode = CipherMode.CBC};

        using (ICryptoTransform encryptor = rijndaelManaged.CreateEncryptor(keyBytes, initVectorBytes))
        {
            using (MemoryStream memoryStream = new MemoryStream())
            {
                using (CryptoStream cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write))
                {
                    cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length);
                    cryptoStream.FlushFinalBlock();

                    byte[] cipherTextBytes = memoryStream.ToArray();
                    encryptedText = Convert.ToBase64String(cipherTextBytes);
                }
            }
        }

        return encryptedText;
    }
}

修改

Sani Huttunen指出，如果您使用相同的密码加密多个数据，我上面的静态实现会出现严重的性能问题。您可以在此处详细了解：http://jmpstart.wordpress.com/2009/09/29/proper-use-of-rfc2898derivebytes/

编辑：如果您需要使用相同的密码执行多次加密/解密，那么非静态实施效率会更高（~32ms原创~1ms新）。

public class SimpleEncryption { #region Constructor public SimpleEncryption(string password) { byte[] passwordBytes = Encoding.UTF8.GetBytes(password); byte[] saltValueBytes = Encoding.UTF8.GetBytes(SaltValue); _DeriveBytes = new Rfc2898DeriveBytes(passwordBytes, saltValueBytes, PasswordIterations); _InitVectorBytes = Encoding.UTF8.GetBytes(InitVector); _KeyBytes = _DeriveBytes.GetBytes(32); } #endregion #region Private Fields private readonly Rfc2898DeriveBytes _DeriveBytes; private readonly byte[] _InitVectorBytes; private readonly byte[] _KeyBytes; #endregion private const string InitVector = "T=A4rAzu94ez-dra"; private const int PasswordIterations = 1000; //2; private const string SaltValue = "d=?ustAF=UstenAr3B@pRu8=ner5sW&h59_Xe9P2za-eFr2fa&ePHE@ras!a+uc@"; public string Decrypt(string encryptedText) { byte[] encryptedTextBytes = Convert.FromBase64String(encryptedText); string plainText; RijndaelManaged rijndaelManaged = new RijndaelManaged { Mode = CipherMode.CBC }; try { using (ICryptoTransform decryptor = rijndaelManaged.CreateDecryptor(_KeyBytes, _InitVectorBytes)) { using (MemoryStream memoryStream = new MemoryStream(encryptedTextBytes)) { using (CryptoStream cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read)) { //TODO: Need to look into this more. Assuming encrypted text is longer than plain but there is probably a better way byte[] plainTextBytes = new byte[encryptedTextBytes.Length]; int decryptedByteCount = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length); plainText = Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount); } } } } catch (CryptographicException exception) { plainText = string.Empty; // Assume the error is caused by an invalid password } return plainText; } public string Encrypt(string plainText) { string encryptedText; byte[] plainTextBytes = Encoding.UTF8.GetBytes(plainText); RijndaelManaged rijndaelManaged = new RijndaelManaged {Mode = CipherMode.CBC}; using (ICryptoTransform encryptor = rijndaelManaged.CreateEncryptor(_KeyBytes, _InitVectorBytes)) { using (MemoryStream memoryStream = new MemoryStream()) { using (CryptoStream cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write)) { cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length); cryptoStream.FlushFinalBlock(); byte[] cipherTextBytes = memoryStream.ToArray(); encryptedText = Convert.ToBase64String(cipherTextBytes); } } } return encryptedText; } }

Answer 2

有一个complete example on MSDN，虽然使用的是RSA而不是TripleDES。

如何加密/解密XML文件？

2 个答案: